JPH0338644B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a composite magnetic head capable of high-density recording and reproduction, and in particular to a magnetic circuit on the recording and reproduction side,
The present invention relates to a joint structure of a back bar that closes an erase side magnetic circuit.

"Prior art and its problems" In a recording method that forms recording tracks along the circumferential direction of a disc-shaped magnetic recording medium such as a magnetic disk, in order to increase the recording density, the track spacing is narrowed. , during recording, there is a crossfeed where adjacent recording tracks overlap, and during playback,
Leakage magnetic flux called crosstalk from adjacent recording tracks is likely to occur.

In order to solve this crosstalk problem, a composite magnetic head as shown in FIGS. 2 and 3 has been proposed. This composite magnetic head is
By scanning both sides in the width direction of the recorded track Tw recorded by the recording/reproducing gap 10, a guard band with almost no signal is created on both sides of the recorded track Tw.
It has the basic function of forming Te. By forming the guard bands Te on both sides of the recording track Tw in this way, even if the track spacing is narrowed,
No crossfeed or crosstalk between adjacent tracks occurs.

This conventional composite magnetic head consists of a magnetic core 11 on the recording/reproducing side and a magnetic core 21 on the erasing side, which are coupled via a non-magnetic layer 29 of ceramics, glass, etc. interposed between the two. . The recording/reproducing side magnetic core 11 and the erasing side magnetic core 21 are each
A pair of magnetic cores 12, 13 and magnetic cores 22, 2
The gaps between the two form the recording/reproducing gap 10 and the erasing gap 20, respectively. Non-magnetic materials 14 and 24, such as high melting point glass, are interposed in the recording/reproducing gap 10 and the erasing gap 20, for example.

Notch grooves 15, 15 are formed on both sides of the recording/reproducing gap 10 in the width direction, spanning between the magnetic cores 12 and 13. These notch grooves 15, 15 are for regulating the track width Tw, and inside thereof,
It is filled with a non-magnetic material (generally glass) 16.

In addition, in the center of the erasing gap 20 in the width direction,
Notch groove 2 with width Ew spanning between magnetic cores 22 and 23
5 is formed. This notched groove 25 regulates the erasing track width Te, and inside it,
Similarly, a non-magnetic material 26 is filled. The width Ew of the cutout groove 25 is set to be approximately the same as or smaller than the recording track width Tw. Further, the length G1 of the notched groove 25 in the track direction is normally set to be 20 times or more the gap interval of the normal erasing gap 20 in order to enable reliable erasing.

Coils 17 and 27 are wound around the magnetic core 13 on the recording/reproducing side and the magnetic core 23 on the erasing side, respectively.
Back bars 18 and 28 are bonded to the back surfaces of and 23, that is, the surfaces opposite to the running surface of the magnetic recording medium. The back bars 18 and 28 are both made of magnetic material, and the magnetic cores 12 and 13 and the back bar 18 constitute a closed magnetic circuit on the recording and reproducing side, and the magnetic cores 22 and 23 and the back bar 28 constitute a closed magnetic circuit on the erasing side. Configure.

However, in this conventional composite magnetic head, the back bars 18 and 28 are separate pieces and must be individually fixed between the magnetic cores 12 and 13 and between the magnetic cores 22 and 23, making the fixing work complicated. Moreover, it was difficult to fix it in the correct position. For example, backbar 1 on the recording/playback side
8 protrudes toward the magnetic core 22 on the erasing side, the magnetic circuit on the recording/reproducing side and the magnetic circuit on the erasing side may not be sufficiently isolated, which may adversely affect both recording/reproducing and erasing. Ta.

OBJECTS OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems with conventional composite magnetic heads and to provide a joining structure in which back bars on the recording/reproducing side and the erasing side can be easily joined. Furthermore, the present invention increases the tolerance for misalignment of the back bar, making it possible to obtain a magnetic head in which a slight misalignment is unlikely to have an adverse effect on both the recording/reproducing and erasing magnetic circuits, and further improving assembly and workability. The purpose is to obtain an excellent magnetic head.

"Summary of the Invention" In order to achieve the above object, the composite magnetic head of the present invention integrates a back bar on the recording/reproducing side and a back bar on the erasing side with a nonmagnetic material sandwiched between them. The back bar is characterized in that the width of the junction with the non-magnetic material interposed therebetween is larger than the width of the junction between the recording/reproducing side (or use) magnetic core and the erasure side (or use) magnetic core.

In this way, by making the width of the joint between the magnetic core on the recording/reproducing side and the magnetic core on the erasing side different from the width of the joint between the back bar, it is possible to increase the tolerance regarding the positional deviation between the magnetic core and the back bar during assembly. It is possible to obtain a magnetic head which is less likely to have an adverse effect on the magnetic circuit due to misalignment, and which is easy to assemble and has excellent workability.

"Embodiments of the Invention" The present invention will be described below with reference to illustrated embodiments. FIG. 1 shows an embodiment of a composite magnetic head according to the present invention, and the same elements as those of the conventional product shown in FIGS. 2 and 3 are given the same reference numerals. This example is
The notched grooves 31 and 32 formed in the recording and reproducing side magnetic core 11 and the erasing side magnetic core 21 are formed not as a through type but as a bottomed type, thereby making the magnetic path of the magnetic cores 12 and 22 thicker and increasing the mechanical strength. The present invention is applied to an increased number of magnetic heads. The bottom walls of the notched grooves 31, 32 are deeper toward the joint surfaces of both cores 11, 21, and are open on the joint surface side. The cutout grooves 31 and 32 have the same function as the cutout grooves 15 and 25 of the conventional product in terms of magnetic recording and reproduction, and their insides are filled with a nonmagnetic material 33 such as glass. This non-magnetic material 33 extends from the communication hole in the bottom of the notch grooves 31 and 32 to the winding groove 34 and
35 also flows into the upper part of the magnetic cores 12 and 13,
and serves to join the magnetic cores 22 and 23 together.

The present invention also provides a back bar 18 on the recording/reproducing magnetic circuit side and a back bar 28 on the erasing side magnetic circuit.
are integrated in advance with a non-magnetic material 40 sandwiched between them, and this integrated back bar 41 is joined to the rear side surfaces of the magnetic cores 11 and 21.

The present invention further provides the above recording/reproducing side magnetic core 1.
A bonding reinforcing groove 50 is formed on the bonding surface between the magnetic core 1 and the erase side magnetic core 21 on the side opposite to the running surface of the magnetic recording medium, and the bonding reinforcing groove 50 is filled with a bonding material 51 made of a non-magnetic material. There is. By forming the bonding reinforcing groove 50 and filling it with the bonding material 51, the magnetic cores 11 and 12 and the magnetic core 2
Since the bonding area with 1 and 22 increases, the bonding strength between both cores can be increased. This joint reinforcement groove 50
The width W of the non-magnetic material 4 of the integrated back bar 41 is
It is set smaller than the width w of 0.

The integrated back bar 41 in which the back bars 18 and 28 are integrated in advance in this way can be more easily fixed to the rear side surface of the magnetic cores 11 and 21 than when the back bars 18 and 28 are separate. Furthermore, by providing a difference between the width W of the bonding reinforcing groove 50 and the width w of the non-magnetic material 40, the integrated back bar 4
The permissible value of displacement in the longitudinal direction of 1 becomes larger. That is, as long as the nonmagnetic material 40 having the width W changes its position within the range of the width W of the bond reinforcing groove 50, the recording/reproducing side back bar 18 is connected to the erasing side magnetic circuit, and the erasing side back bar 28 is connected to the recording/reproducing side magnetic circuit. Since the circuits are not adversely affected, the permissible value of positional deviation is increased.

Note that when the bonding reinforcing groove 50 is not formed on the bonding surface of the magnetic cores 11 and 21, that is, the bonding surface has a thickness s.
If only a thin non-magnetic material 29 of
If the width w of the non-magnetic material 40 of the integrated back bar 41 is made sufficiently larger than this width s, positioning of the integrated back bar 41 will be facilitated as well. That is, since it is sufficient to position the non-magnetic material having the width s within the width w of the non-magnetic material 40, positioning is similarly easy and the tolerance to positional deviation is similarly high.

In the above embodiment, the present invention is applied to a composite type magnetic head in which the cutout grooves 31 and 32 have a special shape, but the present invention is applicable to the conventional magnetic head shown in FIGS. , and other composite magnetic heads.

FIG. 1b shows a state in which sliders 60, 60 are joined to both sides of the composite magnetic head described above.

``Effects of the Invention'' As described above, according to the present invention, in a composite magnetic head, a back bar that closes the recording/reproducing side magnetic circuit and the erasing side magnetic circuit to form a closed magnetic circuit can be easily attached. Positioning becomes easier. Therefore, work efficiency can be improved and costs can be reduced. Further, since tolerance to positional deviation can be increased, it is possible to eliminate adverse effects on the magnetic circuit caused by positional deviation of the back bar.

[Brief explanation of the drawing]

FIG. 1a is a perspective view showing an embodiment of the composite magnetic head of the present invention, FIG. 1b is a perspective view of the slider attached, FIG. 2 is a plan view of a conventional composite magnetic head, and FIG. is a front view of the same. 10... Recording/reproducing gap, 11... Recording/reproducing side magnetic core, 12, 13... Magnetic core, 18...
Back bar, 20... Erasing gap, 21... Erasing side magnetic core, 22, 23... Magnetic core, 28...
...Back bar, 31, 32...Notch groove, 40...
Non-magnetic material, 41... Integrated back bar, 50...
... Bonding reinforcement groove, 51... Bonding material.

Claims (1)

[Scope of Claims] 1. A pair of magnetic cores constituting a recording/reproducing gap, a recording/reproducing back bar located on the back side of the pair of magnetic cores and forming a closed magnetic circuit with the pair of magnetic cores, and the above-mentioned recording/reproducing device. A recording/reproducing magnetic core having cutout grooves located on both sides of the gap to regulate the recording/reproducing track width, and a pair of magnetic cores located on the back side of the pair of magnetic cores forming a pair of erasing gaps located on both sides of the recording/reproducing track. the pair of magnetic cores, an erasing back bar constituting a closed magnetic circuit, and an erasing magnetic core having a notch for regulating the erasing track width by the erasing gap; In a composite magnetic head consisting of a back bar integrated with a back bar with a non-magnetic material interposed therebetween, the width of the joint of the integrated back bar with the non-magnetic material interposed is equal to the width between the recording/reproducing magnetic core and the erasing magnetic core. A back bar joint structure for a composite magnetic head characterized by being larger than the width of the joint.